The present invention is an improvement with respect to a process and product disclosed by Manfrid Dreher in U.K. Specification No. 934,559 published Aug. 21, 1963. For convenience this specification will be designated the "Dreher patent". The Dreher patent discloses the problem sought to be solved by applicant and a partial solution thereto. Dreher suggests forming an article from an age-hardenable alloy while that article is in the solution-treated or soft annealed condition. The formed article, otherwise ready for hardening by aging heat treatment is then plated with gold or a gold alloy. The thus formed plated article is then subjected to an aging treatment suitable for the particular substrate alloy employed and ranging in temperature from 325.degree. C. to 600.degree. C. and in time from 1/2 to 20 hours. By this process, Dreher discloses that he produces components which have excellent mechanical properties and maximum protection against corrosion.
Applicant has exactly the same purposes in mind as did Dreher but, in addition, applicant desires to produce a finished article, component or the like in which the surface precious metal is controllably alloyed so that enhanced wear resistance can be achieved without significantly, detrimentally affecting the character of the precious metal on the object surface. The difficulty with the process of the Dreher patent is that while inherently Dreher must have conceived of the interdiffusion of elements from the age-hardening substrate alloy and the overlayer of gold or other precious metal, no control steps or features are disclosed by Dreher to enable a worker in the art to reliably produce a surfaced article wherein the precious metal surface has reproducible hardness or wear-resistance characteristics as well as corrosion resistance, electrical properties and other features characteristic of a precious metal.